For the full length rifle: Install bent bolt or have your bolt cut, extended and bent. Get a scope mount that fits on the forward ring of the receiver. Buy the $60 Mosin Nagant plastic stock.... The 182 grain Bulgarian (yellowtip) ammo is excellent at 400-600yds. There are several internet sporting goods outifts out there that have the right stuff. Cheaperthandirt, centerfiresystems, (my favorites) and a host of others. We have 3 MG’s in the house. May not be pretty but they are as lethal as any of the $1000 rifles....
Naw. I aint cutting this thing up its 113 years old.
Mine is the second one pictured http://7.62x54r.net/MosinID/MosinM91R.htm